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Profenofos (organophosphate) is among the major toxicant polluting freshwater bodies, exerting a significant effect on fish health. The LC50 value of Profenofos (PRO) was resolved in Grass carp (Ctenopharyngodon idella) with average body weight (55.82 ± 5.42 g) and determined the 96 h LC50 value as 7.2 µg/L for the assay. Twenty-one-day exposures to 1.8 µg/ L and 3.6 µg/ L doses were conducted to evaluate the sub-lethal effects, and various toxicological endpoints were assessed on the 1st, 7th, 15th and 21st days of exposure. Acute toxic stress was observed with fish displaying behavioral toxicity. The most hematological change was extreme microcytic hypochromic anemia. Leucocyte count increased in experimented fish. Moderate neutrophilia, monocytosis and lymphocytosis were observed. Serum total protein, albumin, and globulin concentrations were significantly diminished. Overall, increments over control were recognized in serum urea, creatinine and acid phosphatase. However, serum glucose, total lipid, cholesterol, serum ALT and AST activity showed a significant decrease in fish exposed to both concentrations of PRO. Serum IgM concentrations insignificantly changed in treated fish except for on the 21st day of exposure to 3.6 µg/ L of PRO, while serum lysozyme significantly decreased. Furthermore, total protein, lipid and glycogen concentrations in muscles and the liver exhibited a decreasing trend at all concentrations. Moreover, histopathological alterations in the liver, kidney, and muscles occurred exclusively after treatment. From the obtained results, it is assumed that profenofos induced general toxic impacts under field conditions and might disturb ecologically relevant processes.

The present study evaluated the impact of chronic herbicide (oxyfluorfen; OXY) exposure on catfish, Clarias gariepinus, in terms of growth, hematobiochemical parameters, immune response, antioxidant- and immune-related gene expression, and resistance to monogenean parasites, Quadriacanthus aegypticus. In addition, the protective role of Wormwood, Artemisia cina (AC) against OXY exposure through diet inclusion was also analyzed. The catfish fingerlings were exposed to OXY (1.16 mg/L) for 60 days and fed diets without AC supplementation (control) and with 5% AC supplementation. The results demonstrated that exposure to OXY stunted growth; decreased survival, erythrograms and leukograms, serum protein, and acetylcholinesterase; and negatively altered the antioxidant status. On the contrary, AC supplementation significantly reduced OXY’s negative impacts on growth and hematological, biochemical, and antioxidant balance. In addition, exposure to OXY markedly increased levels of biomarkers of hepatorenal damage, stress indicators, and DNA damage, which were alleviated with AC supplementation. OXY exposure induced immunosuppression manifested by a decrease in lysozyme activities, complement c3, nitric oxide levels, and phagocytic activity. Furthermore, exposure to OXY negatively regulated the expression of immune-antioxidant genes (CAT, GPX1, SOD1, GST, and TGF-Β1). However, it upregulated the expression of CYP1a, IL-1β, and TNF-α in the liver, anterior kidney, and intestine of C. gariepinus. Meanwhile, the addition of AC to the OXY-exposed fish diets notably restored immune components and remedied the altered immune-related gene expressions. Likewise, the AC supplementation significantly alleviated the OXY-induced reduction in the fish survival rate after Q. aegypticus challenge. Accordingly, AC dietary supplementation in catfish diets could alleviate the negative impact of exposure to OXY on growth performance, physiological status, and some immune-antioxidant-related gene expression.

Cadmium (Cd) has become a critical problem in freshwater ecosystems because of both increasing levels and high toxicity. Hence, this study aimed to investigate the effects of dietary supplementation of turmeric powder (TP) alone or in combination with black pepper powder (BPP) on the Cd-induced growth and health disturbances in the African catfish (Clarias gariepinus). A total of 180 healthy fish were divided into six groups in triplicate. The first, second, and third groups were fed on a non-supplemented basal diet, a basal diet supplemented with TP (0.5%), and a basal diet supplemented with TP (0.5%) + BPP (0.1%), respectively. The fourth group was exposed to Cd (0.8 mg/L water) only. The fifth and sixth groups were exposed to Cd and fed on diets supplemented with TP or TP + BPP. The growth performance indicators, somatic indices, whole chemical composition, and Cd residues were evaluated. The liver and kidney function indicators, reproductive hormones, oxidative stress, lipid peroxidation, and adenosine triphosphate (ATP) content were estimated. A histopathological investigation and immunohistochemical detection of the apoptotic marker, caspase 3 of hepatic, renal, and testicular tissues were performed. The results showed that Cd reduced growth, crude lipid, protein, ash contents, and hepatosomatic and gonadosomatic indexes. Moreover, considerably elevated levels of alanine transaminase, alkaline phosphatase, lactate dehydrogenase, urea, creatinine, potassium, and malondialdehyde were recorded. However, a considerable depletion of lysozyme activity, immunoglobulin M, testosterone, estradiol, catalase, and superoxide dismutase in addition to ATP content was evident. The highest amount of Cd was detected in the liver compared with that in the muscles. Moreover, the impairment of hepatic, renal, and testicular tissues architecture with high expression of caspase 3 was prominent. However, the addition of TP and TP + BPP in the diet of Cd-intoxicated fish restored the disturbances in most of the indicators. Notably, the combined TP + BPP supplementation achieved the highest recovery. Overall, TP + BPP mixture can be added in C. gariepinus diet to enhance growth and ameliorate the hepatotoxic, nephrotoxic, and reprotoxic effects of Cd.

Nonylphenol (NP) is a widespread contaminant in the ecosystem. Zinc is an essential trace element with many physiological activities. The existing study aimed to examine the possible favorable role of zinc sulfate against the immunosuppressive, hepatotoxic and nephrotoxic effects of NP in Oreochromis niloticus (O. niloticus). Two hundred and twenty-five tilapia fish were categorized into control, vehicle control, zinc sulfate (0.5 mg/L water), NP (50 μg/L water), and zinc sulfate + NP groups with 3 weeks period of exposure. Selective liver and kidney damaging byproducts, immunological, oxidative stress, lipid peroxidation, hematological, and inflammatory biomarkers were monitored as well as histopathological examinations were performed. The results revealed that NP induced hemolytic anemia, leukocytosis, hyperbilirubinemia, hyponatremia, hyperkalemia, azotemia, hyperproteinemia, hypoalbuminemia, hyper alpha1-globulinemia, hyper alpha2- and beta-globulinemia, and hypo gammaglobulinemia. Also, significantly elevated levels of ALT, AST, LDH, ammonia, cholesterol, creatinine, MDA, MPO, and TNF-alpha were recorded. Meanwhile, ALP, IgM, complement3, and NO levels together with lysozyme activity were significantly declined. Additionally, damage of hepatic and renal structural with splenic lymphoid depletion was also noted. On the contrast, Addition of zinc sulfate into the water restored the disturbances in most of those indicators elicited by NP. It is concluded that zinc sulfate has ameliorative action against hematotoxic, hepatotoxic, nephrotoxic, and immunosuppressive impacts of NP in Nile tilapia fish.

Chlorpyrifos (CPF) is one of the most highly prevalent insecticides in freshwater ecosystems and has been widely detected in fishery and agricultural products worldwide. Moringa oleifera (M. oleifera) is a well-known medicinal plant with many pharmacological properties. Hence, the present study was designed to explore the probable beneficial effect of M. oleifera on CPF-induced health disturbances in Nile tilapia (Oreochromis niloticus). Two hundred and seventy fish were allocated into six groups in triplicate. For 30 days, the first group was fed a basal diet; the second group was exposed to 1/10 of the LC50 of CPF (0.007 mg/L) and fed the basal diet; the third and fourth groups were fed basal diets supplemented with 7% M. oleifera seeds and 10% M. oleifera leaves, respectively; and the fifth and sixth groups were exposed to 1/10 of the LC50 of CPF and fed basal diets supplemented with 7% M. oleifera seeds and 10% M. oleifera leaves, respectively. CPF exposure significantly altered growth performance, haematologic profiles, immune defence mechanisms, liver functions, and oxidant/antioxidant status. Additionally, CPF exposure resulted in prominent genotoxic and lipid peroxidative impacts. Interestingly, dietary supplementation with 7% M. oleifera seeds or 10% M. oleifera leaves significantly counteracted the CPF-induced adverse impacts on O. niloticus growth performance and health. These outcomes show that dietary supplementation with M. oleifera seeds or leaves can safeguard the commercially valuable freshwater fish species O. niloticus against CPF-induced health disorders and may be a candidate feed additive for Nile tilapia in aquaculture.

The aim of the current study was to evaluate the effect of dietary supplementation with mango (Mangifera indica) kernel meal (MKM) and oat (Avena sativa) extract (OE) on growth performance, some serum biochemical parameters, immune status and protection of Oreochromis niloticus against Aeromonas hydrophila infections. A total of 180 Oreochromis niloticus fingerlings were divided to three experimental groups (each of 60 and each group was divided into four aquaria, 15 fish/aquarium); The first group was fed the control diet (without any additive) and the second group was fed diet supplemented with MKM, while the third group was fed diet supplemented with OE for 60 days. Growth performance and immunological parameters (lysozyme, immunoglobulin M) were examined at 2 months of age. Fish were challenged by A. hydrophila and the mortality were recorded after 14 days post-challenge. Fish fed diet contained OE had a higher final body weight, body weight gain and body weight gain percentage when compared with other groups. Immunological parameters estimated in this work were significantly improved (POreochromis niloticus against A. hydrophila.

High fluoride (FL) concentration in many areas of the world is of great concern. It poses a threat to aquatic life. Therefore, the current study was operated to scrutinize the efficiency of Silybum marianum (SM) and/or coenzyme Q10 (CQ10) dietary supplementation to rescue FL negative effects on the growth, hematological indicators, liver and kidney function, serum protein profile, innate immune parameters, oxidative status, vital organ architecture, and disease resistance to Aeromonas sobria. Two hundred and forty healthy Clarias gariepinus fish were alienated into eight groups in triplicate. The control group was fed a non-supplemented basal diet. The SM, CQ10, and SM + CQ10 groups were fed a basal diet fortified with 10 g SM/kg diet, 40 mg CQ10/kg diet, or SM + CQ10, respectively. The FL group was exposed to 73.45 mg FL/L water. The FL + SM, FL + CQ10, and FL + SM + CQ10 were exposed to FL concomitantly with SM, CQ10, and SM + CQ10, respectively. The experiment continued for 60 successive days. The results showed lower weight gain and specific growth rate but higher hepatosomtic index in the FL-exposed fish. An obvious leukopenic and anemic condition was detected. Also, a significant increase in the serum levels of hepatic enzymes and kidney damage products was apparent in FL-exposed fish. Nevertheless, exhaustion of the non-enzymatic and enzymatic antioxidants but elevated lipid peroxidation product (MDA) was noted. The FL exposure exhausted lysozyme activity, complement 3, nitric oxide, total proteins, albumin, and γ globulin contents in the serum of C. gariepinus. Moreover, diverse pathological alterations were detected in the liver, kidney, and spleen. After 14 days of A. sobria challenge, the relative survival rate percentage was significantly reduced in FL-exposed fish. On the contrary, the SM and/or CQ10 addition significantly reduced most FL-associated negative impacts. Conclusively, SM and/or CQ10 dietary supplements could be beneficial for alleviating FL deleterious impacts, thus affording advantageous aqua feed additive for C. gariepinus.

Among toxic pollutants, Mercury (Hg) is a toxic heavy metal that induces harmful impacts on aquatic ecosystems directly and human being's health indirectly. This study confirmed the in vitro magnetic potential of magnetite Nano-Particles (Fe3O4 NPs) against waterborne Hg exposure-induced toxicity in Nile tilapia (Oreochromis niloticus). We further evaluate the safety profile of Fe3O4 NPs on fish growth, hemato-biochemical, histological parameters, bioaccumulation in muscles, and economy. Magnetite nanoparticles were characterized, adsorption loading to Hg ions was investigated, and testing different concentrations of Fe3O4 NPs (0.2, 0.4, 0.6, 0.8, and 1.0 mg/L) was applied to determine the highest concentration of adsorption. An in vivo experiment includes 120 fish with an average weight of 26.2 ± 0.26 g were randomly divided into 4 equal groups, each group had three replicates (n = 30 fish/group; 10 fish/ replicate). All groups were fed on a reference basal diet and the experiment was conducted for 30 days. The first group (G1) was allocated as a control. The second group (G2) received 1.0 mg/L aqueous suspension of Fe3O4 NPs. The third group (G3) was exposed to an aqueous solution of Hg ions at a concentration of 0.025 mg/L. Meanwhile, the fourth group (G4) acquired an aqueous suspension composed of a mixture of Hg ions and Fe3O4 NPs as previously mentioned. Throughout the exposure period, the clinical signs, symptoms, and mortalities were recorded. The Hg ions-exposed group induced the following consequences; reduced appetite resulting in reduced growth and less economic efficiency; microcytic hypochromic anemia, leukocytosis, lymphopenia, and neutrophilia; sharp and clear depletion in the immune indicators including lysozymes activity, immunoglobulin M (IgM), and Myeloperoxidase activities (MPO); significant higher levels of ALT, AST, urea, creatinine, and Superoxide dismutase (SOD); histological alterations of gill, hepatic and muscular tissues with strong expression of apoptotic marker (caspase 3); and a higher accumulation of Hg ions in the muscles. Surprisingly, Fe3O4 NPs-supplemented groups exhibited strong adsorption capacity against the Hg ions and mostly removed the Hg ions accumulation in the muscles. Also, the hematological, biochemical, and histological parameters were recovered. Thus, in order to assess the antitoxic role of Fe3O4 NPs against Hg and their safety on O. niloticus, and fill the gap of the research, the current context was investigated to evaluate the promising role of Fe3O4 NPs to prevent Hg-exposure-induced toxicity and protection of fish health, which ascertains essentiality for sustainable development of nanotechnology in the aquatic environment.

Currently, feed adulteration and contamination with melamine (MEL) are considered one of the serious issues in the aquatic industry. With the limited studies of MEL exposure alone in fish, its adverse impacts on fish cannot be evaluated well. Accordingly, this study aimed to investigate the effects of MEL containing diets on the immune response, disease resistance to Aeromonas hydrophila, growth performance, chemical composition, immune-related genes expression, and histopathology of both spleen and head kidneys. Also, the efficacy of curcumin (CUR) dietary supplementation to alleviate MEL negative impacts were evaluated. A total of 180 apparently healthy Oreochromis niloticus (O. niloticus) were divided into four groups with three replicates fed the basal diet only, basal diet fortified with 200 mg/kg CUR, basal diet containing 1 % MEL, or a basal diet containing CUR + MEL. The results displayed that MEL significantly reduced growth performance indices and body crude lipid contents. Anemic, leukopenic, lymphocytopenic, heterocytopenic, esonipenic, hypoproteinemic and hypoalbuminic conditions were apparent. Moreover, depleted immune and antioxidant indicators including lysozyme activity, nitric oxide, immunoglobulin M, complement 3, glutathione peroxidase, and superoxide dismutase enzyme activity were recorded. Also, MEL reduced the disease resistance of O. niloticus to bacterial infection. Furthermore, MEL induced downregulation of mRNA levels of interleukin 1β and tumor necrosis factor α in the spleen together with obvious pathological perturbations in both spleen and head kidneys. The CUR addition resulted in a significant enhancement in most indices. These results may conclude that MEL could alter both innate and adaptive immune responses via the negative transcriptional effect on immune-related genes together with the oxidative damage of the immune organs. Furthermore, CUR dietary supplements could be advantageous for mitigating MEL negative impacts, thus offering a favorable aquafeed additive for O. niloticus.

The present study evaluated the adverse effects of the hexavalent chromium (Cr (VI)) at sub-lethal concentrations and the ameliorative potential of curcumin (CUR) over a sub-chronic exposure period on Oreochromis niloticus. Fish were exposed to Cr (VI) (4.57 mg/L) and CUR (0.02% in diet or 200 mg/kg diet), individually or in combination for 60-days. The growth rate during the period of experiment, condition factor, body composition, hepatosomatic index (HSI), hematological parameters, oxidative stress, apoptotic and DNA damage, branchial, hepato- and nephrotoxicity were estimated in this study. Moreover, the changes in mRNA expression of Cytochromes (CYP450) and glutathione S-transferase (GST) in kidney and liver tissues were assessed by qRT-PCR. Additionally, the concentration of metallothionine in the liver, histological investigation, and lesion scoring to the branchial, hepatic, renal and gill tissues were applied. The results revealed that Cr (VI) exposure caused a significant decline in most hematological variables and growth rate with down-regulation of CYP450 and GST expression. Histologically, Cr (VI) induced diverse forms of cell injury, vascular, and inflammatory alterations with upregulation of caspase-3 and downregulation of Bcl2 expression in the examined tissues. Additionally, it elevated the levels of serum MDA and 8-hydroxy-2' -deoxyguanosine than control. CUR-supplementation resulted in a significant improvement in most indices, amelioration of histological alterations and up-regulation of CYP450 and GST expression. These results may conclude that dietary supplements with CUR could be useful for modulation of the growth with protective effects to the branchial, hepatic, and renal tissues in response to Cr (VI) exposure, thereby presenting a promising feed additive for Nile tilapia in aquaculture.

This study was conducted to investigate the effects of dietary dried Rocket Leaves meal (DRLM) supplementation on growth performance, immune response, and antioxidant capacity of Oreochromis niloticus reared under different water temperature. For this purpose, five hundred and forty apparently healthy O. niloticus were allocated into nine groups fed three DRLM-supplemented diets (0,1, and 3%) and reared at three water temperature (18, 24, and 32°C) in a 3 × 3 total randomized factorial design. The results revealed that exposure of fish to low (18°C) or high (32°C) temperatures for 30 days evoked significant growth retardation, depleted antioxidant enzymes activities (Catalase; CAT and super oxide dismutase; SOD), lipid peroxidation (malondialdehyde; MDA), immunosuppression, altered cortisol level compared to those reared at 24°C. Moreover, a marked down-regulation of oxidative stress related genes with up-regulation of interleukin 1β gene were apparent. In contrast, DRLM incorporation, particularly at 3%, in heat or cold stressed fish diets significantly enhanced growth, restored IgM and lysozymes levels, and SOD and CAT activities. Also, both the MDA and cortisol levels were significantly depressed. Furthermore, both antioxidant and immune-related genes expression were significantly corrected. Conclusively, 3% DRLM dietary supplementation in tilapia diet could be a promising strategy to alleviate the temperature stress-induced negative impacts on fish health and performance.

To find potential alternatives for certain conventional antibiotics, we investigated the effects of silver nanoparticles (AgNPs) synthesized using Moringa oleifera extract on serum biochemistry, immunological, inflammatory, oxidative, and histological alterations, and DNA damage in Oreochromis niloticus infected with Aeromonas hydrophila. For determining the concentration of AgNPs, 110 fish were used; 11 groups were challenged with Aeromonas hydrophila (each group = 10 fish) and exposed to different concentrations of AgNPs (0, 0.4, 0.8, 1.2, 1.6, 2, 2.4, 2.8, 3.2, 3.6, and 4.0 mg/L) as immersion. Another 360 fish were categorized into eight groups: G1 was non-infected with Aeromonas hydrophila and treated with 0 mg/L AgNPs, G2 was infected and treated with 0 mg/L AgNPs, G3, G4, and G5 were non-infected and treated with 0.4, 0.8, and 1.2 mg/L AgNPs, respectively. G6, G7, and G8 were infected and treated with 0.4, 0.8, and 1.2 mg/L AgNPs, respectively, for seven days. Infection with Aeromonas hydrophila significantly altered the health and reduced lysozyme, hepatic CAT, and hepatic SOD activity, and IgM, complement 3, total protein, albumin, globulin, serum nitric oxide, and IL-10 levels, with a significant increase in the activity of ALT, AST, LDH, and levels of urea, creatinine, bilirubin, hepatic MDA, and inflammatory biomarkers (IL-1β and IL-6). Moreover, the infection produced a prominent genotoxic effect and impaired the architecture of hepatic, renal, splenic, and gill tissues with a strong expression of NF-kB. Fish exposed to different treatments of AgNPs showed improvement in these markers with a significant reduction in the mortality rate. Interestingly, the submersion of infected fish in 0.8 mg/L AgNPs produced the best result. These results showed that green biosynthesis of AgNPs is non-cytotoxic and provides an alternative antimicrobial compound against hepatotoxic, splenotoxic, nephrotoxic, genotoxic, and immunosuppressive impacts of Aeromonas hydrophila in Nile tilapia.

This study was performed to assess the ability of Clostridium perfringens types A and D to induce immunological and inflammatory alterations, and mortalities in Nile tilapia (Oreochromis niloticus). Healthy Nile tilapia (n = 90) with an average body weight of 35 ± 0.5 g were randomly divided into three triplicate groups with ten fish in each aquarium. Fish were injected intraperitoneally (IP) with 0.1 mL of 2.4 × 108 CFU/mL of C. perfringens type A in the first group (G1) and type D in the second group (G2). Fish in the third group (G3) were IP injected with sterile saline and served as control. Clinical signs and postmortem lesions of infected fish started appearing on day 1 post-infection (PI), and the cumulative mortality rates were recorded as 50%, 73%, and 0% in G1, G2, and G3 groups, respectively. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities in the G1 and G2 showed a significant gradual decrease, and reached a peak on day 14, compared to the control group, whereas malondialdehyde (MDA) activity was significantly increased at all-time intervals in G1 and G2. TNF-α showed a significant increase only on day 14 in G1 and G2 compared to the control group. Myeloperoxidase activity (MPO) of both G1 and G2 was increased significantly on day 7 and day 14 compared to the control group and other time periods of exposure. Nitric oxide (NO) activity decreased gradually at 24 h and on day 7 and day 14 for G1 and G2, respectively. The inflammatory biomarker IL-1β showed a significant gradual increase, which reached a peak on day 7 for both G1 and G2 in comparison to control. IL-6 reached a peak on day 14 for G1 and on day 7 for G2. Significant down-regulation of IL-10 occurred on days 7 and 14 post challenge. There was a gradual increase in serum proteins in G1 and G2, which attained a peak on day 14, except γ-globulin, which showed a significant decrease in the same trend. The albumin level decreased gradually in G1 and G2, and among the different periods, and reached a peak at 24 h, followed by on day 7 and finally, on day 14. Lysozyme activity and IgM initially showed a significant increase at 24 h in the G1 and G2 groups compared to the control group and other time periods of exposure; later, decreased gradually on day 7 and day 14. There was a significant decline in complement 3 in G1 and G2 on day 14, followed by day 7 and a significant increase at 24 h. This study has shown that C. perfringens types A and D could be important causative agents of disease and mortality in cultured Nile tilapia species.